渤海西部海域沙垒田凸起古近系边缘断裂构造样式与沉积充填响应

渤海西部海域沙垒田凸起为继承性的古凸起，凸起边缘主要受北西向先存断裂及北东向早期断裂控制，根据控凹主断裂特征以及主断裂、早期同沉积断裂和伴生断裂之间的组合关系，古凸起边缘可划分为同向断阶型边缘、大型低角度正断层控制的缓坡边缘、平直状正断层控制的缓坡边缘,板式正断层控制的陡坡边缘及铲式正断层控制的陡坡边缘和座椅式正断层控制的陡坡边缘等6种。受边缘断裂坡折地貌影响，不同类型凸起边缘沉积相展布和纵向演化具有一定的规律性：同向断阶型凸起边缘，早期盆缘坡折之下发育低位扇三角洲，晚期发育辫状河三角洲前缘加厚带，分隔凸起与缓坡的晚期主干断裂早期控制高位扇三角洲，晚期控制了辫状河三角洲的发育；大型低角度正断层之上发育的同沉积断层控制了沙三段强裂陷期低位扇三角洲、浊积扇的沉积，之后发育缓坡辫状河三角洲_滨浅湖；对于平直状同沉积断层控制的缓坡边缘，沙河街组沉积时期发育缓坡背景下的水进和高位辫状河三角洲，东营组沉积时受断裂坡折影响，坡折之下发育辫状河三角洲前缘加厚带，之上发育辫状河三角洲平原和小型沟谷充填。陡坡边缘沉积充填在垂向上具有分层结构，由早期冲积扇或扇三角洲向辫状河三角洲演变，陡坡坡折控制低位扇三角洲的发育，坡折之上发育沟谷充填和辫状河三角洲平原沉积。

Faulting structure styles and their depositional filling response of thePaleogene margin of Shaleitian uplift,western Bohai Sea area

The NW-trending pre-existing faults and the NE-trending early faults controlled the structural evolution of the Shaleitian uplift margin.According to the characteristics of the main faults,the combination of the main faults,the early synsedimentary faults and the companion faults,Shaleitian uplift margin accommodates the following six kinds of the Paleogene faulting structure styles:concordantfault terrace gentle-slope margin,major low-angle faulted gentle-slope margin,straight normal faulted gentle-slope margin,listric normal faulted steep-slope margin,ramp-flat normal faulted steep-slope margin and platy normal faulted steep-slope margin.Different types of faulted slope-breaks and palaeogeomorphology formed by fault structural styles with early valley developed on the uplift controlled the input and distribution of material source and resulted in different types of raised edge sedimentary filling characteristics.As a result,the plane distribution and vertical evolution of sedimentary facies belts from the uplift to the depression have certain regularity.In concordant fault terrace gentle-slope margin,the low fan-delta developed in early period and the thick braided delta front developed in later period in control of the early basin-margin slope.The main fault which separates Shaleitian uplift and the adjacent depression controlled the development of the high fan-delta in early period and the braided delta in later period.The syndepositional fault which developed on the major low-angle normal fault controlled the deposition of the low fan delta and turbidite fan in the Es₃ member and then developed braided river delta and shore shallow lake in the major low-angle faulted gentle-slope margin.The transgressive and high braided river deltas developed in Shahejie Formation in the straight normal faulted gentle-slope margin,the thick braided deltas front developed below the slope break and the delta plain and small filled valleys developed on the slope break in Dongying Formation.The sedimentary filling has a layered structure in the vertical direction in the edge of the steep slope.From early to late stage,the early alluvial fan or fan delta facies evolved into braided river delta,the steep slope controls the development of the low fan delta,and the delta plain and small filled valleys developed on the slope break.